Jim Cramer, the host of CNBC’s Mad Money and former hedge fund manager who co-founded Thestreet.com, tweeted about Dogecoin, warning investors to be careful with it. Cramer said that the popular meme coin is a security and will be regulated by SEC, as well as questioned the supply of dogecoin.

Many users argued with Cramer on Twitter, questioning the fact that dogecoin, currently the 11th largest cryptocurrency by market cap, is a security. Some even slammed him for his lack of knowledge of blockchains and the meme coin’s supply.